No. 6. 



DEPARTMENT OF AGRICULTURE. 



857 



The value of the crop per acre and weight per bushel for the diller- 

 eut fertilizers applied, are shown in the following table 



TABLE 17. 

 Average Yearly Value of Oats Per Acre. 



o 



Form of Phosphoric Acid 

 Applied in Connection 

 with Nitrogen and 

 Potash. 



I 



Form in which the 



Phosphoric Acid 



Was Applied. 





3 

 u 



be 



^ 



C & I 

 D & J 

 B & H 

 E & K 

 A & G 

 F & L 



Insoluble phosphoric add. 

 Insoluble phusphoiic acid. 

 Reverted phrsphoric acid. 



No phosphoric acid, , 



Soluble phosphoric acid. 

 Nothing, 



Ground bone, 



South Carolina rock, 

 Bone black and lime, 



Bone black. 



39 54 



38 66 



39 47 



38 66 



39 00 

 87 16 



The conclusions, as set forth in the discussion of the above results, 

 in the report, are as follows: 



CONCLUSIONS FROM THE PENNSYLVANIA STATION EXPERIMENTS. 



1. That soluble phosphoric acid is too expensive to be used by 

 farmers having a limestone soil similar to the one on which this 

 experiment was made, since fully as good results can be secured by 

 the use of the much cheaper insoluble form. 



2. That insoluble phosphoric acid in the form of ground bone 

 is slightly superior to that in the form of South Carolina rock. 



3. That corn is benefited more by the application of phosphoric 

 acid than wheat, oats or grass (2-3 clover, 1-3 timothy). 



EXPERIMENTS AT THE MARYLAND STATION. 



These experiments were planned on a more extensive scale than 

 those in Pennsylvania and were conducted with special reference 

 to the making a study of the availability of the different sources 

 of insoluble phosphates. The detailed report upon these experi- 

 ments was made in Bulletin No. 68, of the Maryland Agricultural 

 Experiment Station, published in September, 1900. The following 

 gives a summary as to the plan of the experiments and results: 



PLAN OF THE EXPERIMENTS CONDUCTED. 



The general plan of the experiments conducted in the testing of the 

 aA^ailability of different forms of phosphoric acid and means for 

 rendering insoluble phosphates available in the soil. The idea in 

 mind was to make these tests much more than a soil test of this 



52 



